• Proceedings of the Optical Society of Korea Conference
• /
• 2000.02a
• /
• pp.242-243
• /
• 2000

Erbium 첨가 광섬유(EDF) 광원은 출력 특성과 온도에 대한 파장 특성이 우수하여 Sagnac 간섭계의 원리를 이용한 광섬유 자이로스코프(이하 줄여 자이로라 함)에 많이 사용되고 있다. 이득매질인 EDF를 광원 겸 광증폭기로 사용하는 광섬유 증폭기형 광원 (Fiber Amplifier/source : FAS) 방식$^{[l-2]}$ 은 기존의 single-pass 방식$^{[3]}$ 에 비해서 구조가 단순하고 검출광 power가 크다는 장점이 있다. 그런데, 검출광 power가 큰 경우에 자이로의 SNR이 광원의 과잉잡음(excess noise)에 의해서 제한되므로 실제로 자이로의 측정감도는 개선되지 않는 문제점이 있다.$^{[4]}$ Single-pass 방식의 광원을 사용하는 경우, 적절한 신호처리를 통해 자이로 출력신호에 포함된 광원의 과잉잡음의 적정주파수 성분을 소거함으로써 자이로 신호의 SNR을 개선시킨 바 있었다.$^{[5]}$ 그러나, 일반적으로 single-pass 방식의 경우에는 검출광 power가 작아서 자이로의 SNR이 광원의 과잉잡음에 의해서 제한되는 경우는 드물다. 반면에 증폭기형 광원 방식은 자이로로부터 되돌아오는 신호광이 다시 광원으로 입사되어 EDF를 반대 방향으로 진행하는 동안 증폭되기 때문에 충분히 큰 검출광 power를 얻을 수 있다. 따라서, 자이로 신호에 포함된 광원의 과잉잡음이 소거된다면 자이로 신호의 SNR은 크게 개선될 것으로 여겨진다. 이 논문에서는 광섬유 증폭기형 광원 방식(FAS)의 자이로에 대해 위와 같은 신호처리를 이용하여 광인의 과잉잡음의 적정주파수 성분을 소거하는 실험을 하였다. (중략)한 흡수를 확인하고, $^4$T$_2$$\longrightarrow$$^4$A$_2$(650-800 nm), $^2$E$\longrightarrow$$^4$A$_2$에 의한 nophonon line R$_1$, R$_2$(680.4, 678.5 nm) 및 $^2$T$_1$$\longrightarrow$$^4$A$_2$(655.7, 649.3, 645.2 nm)의 형광방출 스펙트럼을 얻었으며, 형광수명은 0.264 ms로 조사되었다. 제조된 레이저 발진봉은 직경 6.3 m, 길이 45 nm이었다.\pm$0.06kHz Ge $F_4$; -1.84$\pm$0.04kHz$0.04kHz/TEX>0.04kHz 모국어 및 관련 외국어의 음운규칙만 알면 어느 학습대상 외국어에라도 적용할 수 있는 보편성을 지니는 것으로 사료된다.없다. 그렇다면 겹의문사를 [-wh]의리를 지 닌 의문사의 병렬로 분석할 수 없다. 예를 들어 누구누구를 [주구-이-ν가] [누구누구-이- ν가]로부터 생성되었다고 볼 수 없다. 그러므로 [-wh] 겹의문사는 복수 의미를 지닐 수 없 다. 그러면 단수 의미는 어떻게 생성되는가\ulcorner 본 논문에서는 표면적 형태에도 불구하고 [-wh]의미의 겹의문사는 병렬적 관계의 합성어가 아니라 내부구조를 지니지 않은 단순한 단어(minimal $X

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.22 no.5
• /
• pp.227-232
• /
• 2012

Inconel 617 and Hastelloy X are the most promising candidate materials for the heat exchanger of next generation nuclear reactor. Surface coating and its effects on high temperature properties for the Inconel 617 and Hastelloy X under molten FLiNaK (LiF-NaF-KF) salt environment have been investigated. For TiAlN and $Al_2O_3$ overlay coatings, the two different PVD (physical vapor deposition) methods of an arc discharge and a sputtering were applied, respectively. A study for the thermal stability of the surface modified Ni-Cr alloy substrates has been conducted. To evaluate the corrosion mechanism of Ni-Cr alloys in the molten salt, a ruptured Inconel pipe used for the molten salt transportation has been analyzed. The thermal properties of morphological and structural properties each sample were characterized before and after heat-treatment at $600^{\circ}C$ in molten FLiNaK salt. The results showed that the TiAlN and $Al_2O_3$ overlay coated specimens had the enhanced high temperature stability.

• Journal of Advanced Navigation Technology
• /
• v.18 no.1
• /
• pp.35-43
• /
• 2014

In this paper, it is about to non-contact wireless power transmission according to various conditions of self induction principle between the two planar coils at a transmission unit and a receiving unit based on the theory of wireless power transmission. The experiments are occurred in order to power transfer of noncontact method from designed wireless circuits in the primely coil and secondary coil, and the applying to Half Bridge Resonant converter transmission unit and receiving unit. and that were able to prepared circumstance to calculate of the output voltage and power source. The main power of the inductive coupling the resonant converter at the transmission unit is converted electrical energy using the solar cell module and artificial light source (halogen lamp) as a replace light and received 24 V power supply from solar power was used a input power source for the wireless power transmission device. Experimental results, to received of power is used to illuminate the lighting and to charge the battery in receiving circuit.And the wireless power transmission efficiency measured at the output side of the transmission unit is obtained about 70% to 89% compared to input power of receiving unit.In addition, efficiency were tested through ID verification method and comparing the phase difference between the voltage when foreign substances interfere with wireless power transmission.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.12
• /
• pp.638-643
• /
• 2017

The 3D laser scanner operates by measuring the distance from the sensor to the target and operates on the same principle as Electronic Distance Measuring (EDM). Recently, 3D laser scanning technology has been rapidly developed in line with the strongly increasing demand for 3D information acquisition. Therefore, it is now possible to more easily acquire geometric information of various objects existing in real space. In this study, we constructed geospatial information by using new equipment which integrated 3D laser scanner and total station, and we suggest the possibility of using new technology for geospatial information construction by comparing and analyzing with existing methods. In the study result, we demonstrated the efficiency of the geospatial information constructed by integration of 3D laser scanner and total station. The proposed method is expected to shorten the time required for data acquisition compared to the existing method using the existing total station. Furthermore, it is possible to use various methods such as cross section analysis and volume calculation using the acquired data. In the future, spatial information construction by integration of 3D laser scanner and total station will help improve work efficiency in related fields.

• Smart Media Journal
• /
• v.2 no.4
• /
• pp.60-65
• /
• 2013

In this paper, we propose a high-resolution disparity map generation method using a low-resolution time-of-flight (TOF) depth camera and color camera. The TOF depth camera is efficient since it measures the range information of objects using the infra-red (IR) signal in real-time. It also quantizes the range information and provides the depth image. However, there are some problems of the TOF depth camera, such as noise and lens distortion. Moreover, the output resolution of the TOF depth camera is too small for 3D applications. Therefore, it is essential to not only reduce the noise and distortion but also enlarge the output resolution of the TOF depth image. Our proposed method generates a depth map for a color image using the TOF camera and the color camera simultaneously. We warp the depth value at each pixel to the color image position. The color image is segmented using the mean-shift segmentation method. We define a cost function that consists of color values and segmented color values. We apply a weighted average filter whose weighting factor is defined by the random walk probability using the defined cost function of the block. Experimental results show that the proposed method generates the depth map efficiently and we can reconstruct good virtual view images.

• Journal of Environmental Impact Assessment
• /
• v.25 no.1
• /
• pp.63-76
• /
• 2016

In 2015, Summits of State and Government at United Nations General Assembly agreed to set the world on a path towards Sustainable Development(SD) through the adoption of the 2030 Agenda. 2030 Agenda adopts 17 Sustainable Development Gooals(SDG) to achieve 3 pillars of social security, economic efficiency and environmental integrity. Sustainable Development Indicators(SDI) which are suggested by UN SDSN(United Nations Sustainable Development Solutions Network), have been developed for measuring SDG implementation, by which Sustainability Assessment(SA) can be accomplished to check through more holistic approaches to poverty alleviation, social inclusion and environmental management. In Korea, Strategic Environmental Impact Assessment(SEIA) has been applied to PPP(policy, plan, program) by 'Ministry of Environment', whereas 'National Land Planning Assessment(NLPA) which is one sort of SEA has been implemented to evaluate PPP of Ministry of Land, Infrastructure and Transport'. Although SEIA and NLPA have been utilized as decision-making support tools for stakeholders including high authorities, the reference criteria of these institutions are not considered as convincible and communicable. Evaluation criteria of alternatives which are core principles for SEIA and NLPA seem so ambiguous and unscientific. Through incorporation of SDI into SEIA, a convenient, quick and credible diagnosis of the key dimensions of SD comprising social equity, economic development and environmental management, can help develop a shared understanding of priorities of implementation of SDG.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.41 no.7
• /
• pp.665-671
• /
• 2017

The alkali-Metal Thermal-to-electric Converter (AMTEC) is one of the promising static energy conversion technologies for the direct conversion of thermal energy to electrical energy. The advantages over a conventional energy converter are its high theoretical conversion efficiency of 40% and power density of 500 W/kg. The working principle of an AMTEC battery is the electrochemical reaction of the sodium through an ion conducting electrolyte. Sodium ion pass through the hot side of the beta"-alumina solid electrolyte (BASE) primarily as a result of the pressure difference. This pressure difference across the BASE has a significant effect on the overall performance of the AMTEC system. In order to build the high pressure difference across the BASE, hermeticity is required for each joined components for high temperature range of $900^{\circ}C$. The AMTEC battery was manufactured by utilizing robust joining technology of BASE/insulator/metal flange interfaces of the system for both structural and electrical stability. The electrical potential difference between the anode and cathode sides, where the electrons emitted from sodium ionization and recombined into sodium, was characterized as the open-circuit voltage. The efforts of technological improvement were concentrated on a high-power output and conversion efficiency. This paper discusses about the joining and performance of the AMTEC systems.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.12 no.1
• /
• pp.62-65
• /
• 2008

Purpose: Vitamin $B_{12}$ and folic acid are type of water-soluble vitamin and those work as a secondary vital enzyme, but especially those are involved in the nuclear DNA synthesis. Those are mainly measured in order to diagnose megaloblastic anemia and to assess the storage of folic acid during pregnancy. It is generally known that the hemolyzed serum is useless for folic acid and vitamin $B_{12}$, but it is not easy to abide by this information because our lab (Samkwang Medical Laboratories) is reference laboratory. We tested how much the extent of hemolyzed serum had influence on the results. Materials and Method: We performed the tests of vitamin $B_{12}$, folic acid. For the hemolysis effect study, we used 40 cases. According to the level of A, B and C groups, each group had 10 samples which were mechanically hemolyzed serum. Results: Hemolysis did not affect the vitamin $B_{12}$ results. However in case of folic acid, the value increased according to the degree of hemolysis. And severe hemolyzed cases had the highest value (greater than 20 ng/ml). Conclusions: Preventing the hemolysis, it has to be informed that blood-collecting, separation and storage are performed more carefully. As you see from the above results, hemolyzed serum is not proper for folic acid test, and hemolysis does not affect the results of vitamin $B_{12}$. However, for the more accurate results, it is necessary to avoid hemolysis.

• Communications of Mathematical Education
• /
• v.24 no.2
• /
• pp.325-344
• /
• 2010

The purpose of this study is to investigate what influences students' preferences on empirical and deductive proofs and find their relations. Although empirical and deductive proofs have been seen as a significant aspect of school mathematics, literatures have indicated that students tend to have a preference for empirical proof when they are convinced a mathematical statement. Several studies highlighted students'views about empirical and deductive proof. However, there are few attempts to find the relations of their views about these two proofs. The study was conducted to 47 students in 7~9 grades in the transition from empirical proof to deductive proof according to their mathematics curriculum. The data was collected on the written questionnaire asking students to choose one between empirical and deductive proofs in verifying that the sum of angles in any triangles is $180^{\circ}$. Further, they were asked to provide explanations for their preferences. Students' responses were coded and these codes were categorized to find the relations. As a result, students' responses could be categorized by 3 factors; accuracy of measurement, representative of triangles, and mathematics principles. First, the preferences on empirical proof were derived from considering the measurement as an accurate method, while conceiving the possibility of errors in measurement derived the preferences on deductive proof. Second, a number of students thought that verifying the statement for three different types of triangles -acute, right, obtuse triangles - in empirical proof was enough to convince the statement, while other students regarded these different types of triangles merely as partial examples of triangles and so they preferred deductive proof. Finally, students preferring empirical proof thought that using mathematical principles such as the properties of alternate or corresponding angles made proof more difficult to understand. Students preferring deductive proof, on the other hand, explained roles of these mathematical principles as verification, explanation, and application to other problems. The results indicated that students' preferences were due to their different perceptions of these common factors.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2007.05a
• /
• pp.1214-1218
• /
• 2007

댐 하류로 탁수를 선택적으로 배제하기 위해서는 방류 탁수가 하류에 미치는 영향을 정확히 예측할 수 있는 하천 탁도 예측 및 관리시스템 구축이 필요하다. 낙동강과 반변천의 합류부에서의 이차원적인 혼합에 관한 수치해석 결과는 완전혼합을 가정하는 일차원 수질모델링의 초기 입력자료에 사용됨으로써 낙동강 본류 전체구간의 탁도 모의결과의 정확성을 높이는 데 사용될 수 있다. 본 연구는 낙동강의 중상류에 위치한 반변천 합류부에 평면 이차원 비정상 수치모형인 KU-RLMS 모형을 적용하여 탁도 변화 특성을 규명할 목적으로 수행하였다. KU-RLMS 모형은 하천 및 저수지의 국부적인 수리, 수질, 유사이동 해석을 위해 개발된 평면 이차원 비정상 수치모형이다. 직사각형 격자를 사용하는 유한차분법의 단점을 보완하기 위해, 수심적분된 2차원 연속방정식, 운동량방정식, 이송확산방정식을 불규칙한 경계를 현실적으로 모사할 수 있는 직교곡선 좌표계로 변환한 방정식을 사용한다. 이 모형은 흐름, 농도, 지형변화를 조합하여 계산할 수 있는 모형으로서 점착성 및 비점착성 유사의 이동을 모의할 수 있다. 수치모형 적용을 위한 현황분석으로 안동 및 임하 조정지댐의 방류량, 안동 수위관측소의 수위, 법흥교 및 포진교 지점의 탁도 자료를 분석하였다. 이송확산모형의 보정을 위해, 안동대교 지점의 탁도 횡분포 측정 자료를 사용하여 확산계수에 대한 매개변수 추정 및 검증을 수행하였다. 또한, 안동조정지댐과 임하조정지댐의 방류량 및 방류탁도을 고려하여 수치모의조건을 결정하였으며, 각 조건에 대한 탁도 변화 특성을 분석하였다.된 주변국이 될 수밖에 없을 것이다. 21세기 문화산업에서 우리가 판단하게 될 디자인의 가치는 계몽의 원리에 대한 '역사성'과 '현재성'의 변증법에 달려있는 것이며, 새로운 철학, 새로운 문명, 새로운 세계를 열어가는 것이다.r$ (地理志)에는 추현리와 이미 외리를 언급하면서 상주의 자기제작의 위상을 짐작하는 기록이 언급되면서 전국의 상품의 절반을 담당하고 있었음을 알 수 있었다. $\ulcorner$경상도지리지$\lrcorner$(慶尙道地理志)에는 상주가 8곳으로 1/3의 자기 생산을 담당하고 있었다. $\ulcorner$경상도지리지$\lrcorner$(慶尙道地理志)에는 $\ulcorner$세종실록$\lrcorner$(世宗實錄) $\ulcorner$지리지$\lrcorner$(地理志)와 동년대에 동일한 목적으로 찬술되었음을 알 수 있다. $\ulcorner$경상도실록지리지$\lrcorner$(慶尙道實錄地理志)에는 $\ulcorner$세종실록$\lrcorner$(世宗實錄) $\ulcorner$지리지$\lrcorner$(地理志)와의 비교를 해보면 상 중 하품의 통합 9개소가 삭제되어 있고, $\ulcorner$동국여지승람$\lrcorner$(東國與地勝覽) 에서는 자기소와 도기